In order to achieve our long-term goalssupporting research to reduce new infections, improve health outcomes for those infected, and reduce disparities-we need to be at the cutting edge of scientific methods. Rigorous HIV science relies on optimal methods to address research questions. Investigators increasingly require timely, accessible, and specialized input to learn, select, and implement best practices in research design and measurement as well as data acquisition, management, and analysis. To meet these needs, the Methods Core provides expert methodological support through seminars, trainings, individual consultations, and peer review. By implementing the following aims, the Methods Core will foster innovative HIV science. The Methods Core collaborates with and supports CAPS scientists through all steps of the research process, from idea generation to the dissemination of final results. Reflecting the Center's long-term goals in the proposed funding period, the core will continue its strong record of support for CAPS scientists in a broad variety of research methods.